Cyborg-Like Bionics Harness Sunlight

PORTLAND, Ore. — Using design principles that marry the building-blocks of biological organisms to semiconductors, researchers are creating the precursors of bionic supra-particles that could someday be assembled into cybernetic organisms -- cyborgs -- like those made popular by the Orion Pictures movie Terminator according to University of Michigan professor Nicholas Kotov.

"These supra-particles are reminiscent of some parts of cells called peroxisomes," Kotov who led the experiment with fellow University of Michigan professor Sharon Glotzer, along with colleagues at the University of Pittsburgh. "The self-assembly takes place in water by mixing the inorganic and organic nano-particles with an enzyme." The researchers first bionic supra-particle combined the semiconductor cadmium telluride -- which is used in solar cells to convert sunlight into free electrons -- with the living protein cytochrome C, which is used by plants to transport electrons in photosynthesis. By choosing different enzymes to self-assemble onto the half-semiconductor/half-protein supra-particle, the transported electrons can perform biological-like functions, such as producing fuel to drive a cyborg. Kotov believes that such bionic supra-particles could someday be used to create Terminator-like cyborgs (hopefully benevolent ones). "Stay tuned. We are not done yet," Kotov told EE Times.

Artist's rendering of bionic supra-particles may one day harnessing sunlight to make fuels.
(Credit: Trung Nguyen; Source: University of Michigan)

In the nearer term, bionic supra-particles could be used to covert dangerous pollutants into harmless substances, perhaps even cleanse the atmosphere of green-house gases like carbon dioxide (CO2). Unfortunately, the bionic supra-particles act as catalysts that are sometimes damaged while doing their work, however their ability to self-assemble could enable them to repair that damage the same way plants do to their catalytic structures which are damaged during photosynthesis.

Kotov told EE Times:

There are many enzymes that can destroy toxic organic compounds. They can certainly be used in supra-particles to clean up pollution. In this case the ability of inorganic nano-particles to absorb light and provide the energy needed for destruction of these toxic compounds will be particularly useful. One particular pollution in which we are much interested is CO2 pollution. There are enzymes that can transform it into useful compounds. The ability of supra-particles to self-assemble and potentially to self-repair themselves would be quite useful here.

Another project that Kotov's team is working on is converting carbon dioxide and water into natural gas, thereby cleansing the atmosphere of a dangerous green-house gas while simultaneously boosting the industrial and household energy infrastructure with a process that has no net carbon emissions. The task, however, will require many engineering hurdles to be surmounted to catalyze the reaction.

"Catalysis of this reaction is difficult because of the large number of electrons that we need to transport to an atom of carbon," Kotov told EE Times. "Accomplishing this task is difficult, because this process requires a lot of energy and carrying it out damages the catalyst itself."

A different artist's rendering of bionic supra-particles may one day be the building blocks of cybernetic organisms. (Credit: Trung Nguyen;
Source: University of Michigan)

Glotzer, who led the simulations team, says they formula for the supra-particles self-assemble into a size of about 100 nanometers in diameter. In tests built on this formula, the supra-particle was impregnated with enzymes that were able to turn the pollutant nitrate into nitrite and oxygen using sunlight as the driving energy.

Funding was supplied by the Department of Energy, National Science Foundation, Army Research Office, Department of Defense and National Institutes of Health.